Systems and methods for interference mitigation in heterogeneous networks

• US 8,805,394 B2
• Filed: 09/27/2012
• Issued: 08/12/2014
• Est. Priority Date: 05/17/2012
• Status: Expired due to Fees

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Ibrahim, Ahmed S., Makled, Esraa A., Elgebaly, Hani H., Darwish, Ahmed M.
• Primary Examiner(s): DOAN, KIET M
• Application Number:
  US13/629,015
• Publication Number:
  US 20130310058A1
• Time in Patent Office: 684 Days
• Field of Search: 455/450, 455/522, 455/405, 455/423, 455/418, 455/422.1, 455/436, 455/452.1, 455/437, 370/252, 370/336, 370/328
• US Class Current: 455/452.1
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/265 taking into account the quality of service QoS
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Disclosed systems and methods mitigate interference in heterogeneous networks. Embodiments include adaptive or selective inter-cell interference coordination, adaptive multi-user zero forcing, adaptive power, and/or combinations of the foregoing. Techniques may be used to favor one group of users (e.g., femto users or macro users) over another. Certain embodiments focus quality of service (QoS) improvements on a first group of users, while using constraint processes to provide a threshold QoS for a second group of users.

Claims

1. A method for interference mitigation in a heterogeneous network including one or more femto cells within a macro cell coverage area, the method comprising:

transmitting, at a femto station, wireless communication signals using a plurality of femto station resources to communicate with at least one femto user equipment (UE) within a femto coverage area of the femto station, wherein the plurality of femto station resources are divisions of a shared medium available to the femto station;

detecting, at the femto station, that a macro UE is operating within the femto coverage area, wherein the macro UE is coupled to a macro station;

in response to detecting the macro UE, shutting off a first portion of the femto station resources and transmitting the wireless communication signals using a second portion of the femto station resources, wherein the first portion of the femto station resources are a source of interference to the macro UE,

wherein detecting the macro UE operating within the coverage area of the femto station comprises;

measuring a first power of a first signal received at the femto station from the macro UE;

receiving, at the femto station, a message from a macro station indicating a second power of a second signal received at the macro station from the macro UE; and

determining that the first signal is greater than the second signal, the determination indicating that the macro UE is detected within the coverage area of the femto station.

2. The method of claim 1, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

receiving, at the femto station, a message from the macro UE indicating that power of a first signal received by the macro UE from a macro station is lower than power of a second signal received from the femto station.

3. The method of claim 1, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

receiving a location message, at the femto station, indicating a geographic location of the macro UE; and

determining that the geographic location of the macro UE is within the coverage area of the femto station.

4. The method of claim 3, wherein the location message is received from the macro UE.

5. The method of claim 3, wherein the location message is received from a macro station.

6. The method of claim 1, further comprising:

selectively adjusting a percentage of the plurality of femto station resources included in the first portion that are shut off as a function of desired capacity available to the at least one femto UE versus a desired improvement in a quality of service provided to the macro UE.

7. The method of claim 6, wherein increasing the percentage of the plurality of femto station resources included in the first portion decreases the capacity available to the at least one femto UE.

8. The method of claim 1, wherein one or more of the plurality of femto station resources included in the first portion comprise at least one of a time resource block and a frequency resource block.

9. The method of claim 1, further comprising:

determining that the macro UE is no longer operating within the femto coverage area; and

in response to the determination, turning on the first portion of the femto station resources to transmit the wireless communication signals using both the first portion and the second portion of the femto station resources.

10. The method of claim 1, wherein the at least one femto UE is associated with a closed subscription group (CSG) that grants access to communicate through the femto station, and wherein the macro UE is not associated with the CSG and is not granted access to communicate through the femto station.

11. The method of claim 1, further comprising:

setting a first transmission power of the femto station;

at the first transmission power, measuring a quality of service (QoS) for the at least one femto UE within the femto coverage area;

comparing the measured QoS for the at least one femto UE with a first target QoS; and

incrementally increasing the power of the femto station from the first transmission power to a second transmission power at which the first target QoS is met for each of the at least one femto UE within the femto coverage area.

12. The method of claim 11, further comprising, before each incremental increase in the power of the femto station:

measuring a QoS for the macro UE detected within the femto coverage area;

comparing the measured QoS for the macro UE with a second target QoS; and

in response to determining that the second target QoS is satisfied for the macro UE, allowing the incremental increase in the power of the femto station.

13. The method of claim 1, further comprising:

setting a first transmission power of the femto station;

at the first transmission power, measuring a quality of service (QoS) for the macro UE detected within the femto coverage area;

comparing the measured QoS with a first target QoS; and

decrementing the power of the femto station from the first transmission power to a second transmission power at which the first target QoS is met for the macro UE within the femto coverage area.

14. The method of claim 13, further comprising, before each decrement in the power of the femto station:

measuring a QoS for the at least one femto UE within the femto coverage area;

comparing the measured QoS for the at least one femto UE with a second target QoS; and

in response to determining that the second target QoS is satisfied for the at least one femto UE within the femto coverage area, allowing the decrement in the power of the femto station.

15. A non-transitory machine readable storage medium having stored thereon instructions, which when executed by a processor, cause the processor to perform a method comprising:

transmitting, from a transceiver, wireless communication signals using a plurality of resources to communicate with a first user equipment (UE) within a coverage area of the transceiver, wherein the plurality of femto station resources are divisions of a shared medium available to the femto station;

detecting, at the transceiver, that a second UE is operating within the coverage area wherein the second UE is coupled to a macro station;

in response to detecting the second UE, shutting off a portion of the resources to reduce interference to the second UE,

wherein detecting the macro UE operating within the coverage area of the femto station comprises;

measuring a first power of a first signal received at the femto station from the macro UE;

receiving, at the femto station, a message from a macro station indicating a second power of a second signal received at the macro station from the macro UE; and

determining that the first signal is greater than the second signal, the determination indicating that the macro UE is detected within the coverage area of the femto station.

16. The machine readable storage medium of claim 15, the method further comprising:

setting a first transmission power of the transceiver;

at the first transmission power, measuring a quality of service (QoS) for the first UE within the coverage area;

comparing the measured QoS for the first UE with a first target QoS; and

incrementally increasing the power of the transceiver from the first transmission power to a second transmission power at which the first target QoS is met for the first UE within the coverage area.

17. The machine readable storage medium of claim 16, the method further comprising, before each incremental increase in the power of the transceiver:

measuring a QoS for the second UE detected within the coverage area;

comparing the measured QoS for the second UE with a second target QoS; and

in response to determining that the second target QoS is satisfied for the second UE, allowing the incremental increase in the power of the transceiver.

18. The machine readable storage medium of claim 15, the method further comprising:

setting a first transmission power of the transceiver;

at the first transmission power, measuring a quality of service (QoS) for the second UE detected within the coverage area;

comparing the measured QoS with a first target QoS; and

decrementing the power of the transceiver from the first transmission power to a second transmission power at which the first target QoS is met for the second UE.

19. The machine readable storage medium of claim 18, the method further comprising, before each decrement in the power of the transceiver:

measuring a QoS for the first UE within the coverage area;

comparing the measured QoS for the first UE with a second target QoS; and

in response to determining that the second target QoS is satisfied for the first UE within the coverage area, allowing the decrement in the power of the transceiver.

20. A method for interference mitigation in a heterogeneous network including one or more femto cells within a macro cell coverage area, the method comprising:

transmitting, at a femto station, wireless communication signals using a plurality of femto station resources to communicate with at least one femto user equipment (UE) within a femto coverage area of the femto station;

detecting, at the femto station, that a macro UE is operating within the femto coverage area, wherein the macro UE is coupled to a macro station;

setting a first transmission power of the femto station;

at the first transmission power, measuring a quality of service (QoS) for the at least one femto UE within the femto coverage area;

comparing the measured QoS for the at least one femto UE with a first target QoS;

incrementally increasing the power of the femto station from the first transmission power to a second transmission power at which the first target QoS is met for each of the at least one femto UE within the femto coverage area;

measuring a QoS for the macro UE detected within the femto coverage area;

comparing the measured QoS for the macro UE with a second target QoS; and

in response to determining that the second target QoS is satisfied for the macro UE, allowing the incremental increase in the power of the femto station, and

further comprising in response to detecting the macro UE, shutting off a first portion of the femto station resources and transmitting the wireless communication signals using a second portion of the femto station resources, wherein the first portion of the femto station resources are a source of interference to the macro UE and wherein the plurality of femto station resources are divisions of a shared medium available to the femto station.

21. The method of claim 20, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

receiving, at the femto station, a message from the macro UE indicating that power of a first signal received by the macro UE from a macro station is lower than power of a second signal received from the femto station.

22. The method of claim 20, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

measuring a first power of a first signal received at the femto station from the macro UE;

receiving, at the femto station, a message from a macro station indicating a second power of a second signal received at the macro station from the macro UE; and

determining that the first signal is greater than the second signal, the determination indicating that the macro UE is detected within the coverage area of the femto station.

23. The method of claim 20, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

receiving a location message, at the femto station, indicating a geographic location of the macro UE; and

determining that the geographic location of the macro UE is within the coverage area of the femto station.

24. The method of claim 23, wherein the location message is received from the macro UE.

25. The method of claim 23, wherein the location message is received from a macro station.

26. The method of claim 20, wherein the at least one femto UE is associated with a closed subscription group (CSG) that grants access to communicate through the femto station, and wherein the macro UE is not associated with the CSG and is not granted access to communicate through the femto station.

27. A method for interference mitigation in a heterogeneous network including one or more femto cells within a macro cell coverage area, the method comprising:

transmitting, at a femto station, wireless communication signals using a plurality of femto station resources to communicate with at least one femto user equipment (UE) within a femto coverage area of the femto station;

detecting, at the femto station, that a macro UE is operating within the femto coverage area, wherein the macro UE is coupled to a macro station;

setting a first transmission power of the femto station;

at the first transmission power, measuring a quality of service (QoS) for the macro UE detected within the femto coverage area;

comparing the measured QoS with a first target QoS;

decrementing the power of the femto station from the first transmission power to a second transmission power at which the first target QoS is met for the macro UE within the femto coverage area;

measuring a QoS for the at least one femto UE within the femto coverage area;

comparing the measured QoS for the at least one femto UE with a second target QoS; and

in response to determining that the second target QoS is satisfied for the at least one femto UE within the femto coverage area, allowing the decrement in the power of the femto station, and

further comprising in response to detecting the macro UE, shutting off a first portion of the femto station resources and transmitting the wireless communication signals using a second portion of the femto station resources, wherein the first portion of the femto station resources are a source of interference to the macro UE and wherein the plurality of femto station resources are divisions of a shared medium available to the femto station.

28. The method of claim 27, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

receiving, at the femto station, a message from the macro UE indicating that power of a first signal received by the macro UE from a macro station is lower than power of a second signal received from the femto station.

29. The method of claim 27, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

measuring a first power of a first signal received at the femto station from the macro UE;

receiving, at the femto station, a message from a macro station indicating a second power of a second signal received at the macro station from the macro UE; and

determining that the first signal is greater than the second signal, the determination indicating that the macro UE is detected within the coverage area of the femto station.

30. The method of claim 27, wherein detecting the macro UE operating within the coverage area of the femto station comprises:

receiving a location message, at the femto station, indicating a geographic location of the macro UE; and

determining that the geographic location of the macro UE is within the coverage area of the femto station.

31. The method of claim 30, wherein the location message is received from the macro UE.

32. The method of claim 30, wherein the location message is received from a macro station.

33. The method of claim 27, wherein the at least one femto UE is associated with a closed subscription group (CSG) that grants access to communicate through the femto station, and wherein the macro UE is not associated with the CSG and is not granted access to communicate through the femto station.